The present invention relates to a tool in general, more particularly to a tool for shaping of sheet metal. Still more specifically, the invention relates to a drawing tool for shaping of sheet metal.
Tools of this type are used, for example, to shape kitchen sinks from one-piece sheets of metal, usually stainless steel. Such tools have an upper part and a lower part between which the sheet metal to be shaped is placed, and of which at least one is movable relative to the other toward and away therefrom. One of the parts has a matrix and a drawing ring with drawing edges and the other tool part has a usually fixed drawing die and a sheet metal holder which is movable relative to the drawing die. Conventionally, such sheet metal holders are supported--if small tools are involved--by springs; if larger tools are involved or tools for larger parts to be drawn are involved, the sheet metal holders are supported against a drawing cushion of a press which holds the tool.
These prior-art arrangements are not fully satisfactory, particularly because if relatively large sheet metal members are to be shaped by drawing, presses with integrated drawing cushions are required against which the sheet metal holders are supported via pressure bolts. The drawing of such sheet metal parts thus requires the presence of double-acting presses and cannot be carried out on single-acting presses. This is a disadvantage because there are many instances where a double-acting press is not available and/or it is not economically feasible to acquire one.